Drug Resistance In Renal Cell Carcinoma Research Articles

DEPDC1 as a metabolic target regulates glycolysis in renal cell carcinoma through AKT/mTOR/HIF1α pathway

Renal cell carcinoma (RCC) is considered a “metabolic disease” characterized by elevated glycolysis in patients with advanced RCC. Tyrosine kinase inhibitor (TKI) therapy is currently an important treatment option for advanced RCC, but drug resistance may develop in some patients. Combining TKI with targeted metabolic therapy may provide a more effective approach for patients with advanced RCC. An analysis of 14 RCC patients (including three needle biopsy samples with TKI resistance) revealed by sing-cell RNA sequencing (scRNA-seq) that glycolysis played a crucial role in poor prognosis and drug resistance in RCC. TCGA-KIRC and glycolysis gene set analysis identified DEPDC1 as a target associated with malignant progression and drug resistance in KIRC. Subsequent experiments demonstrated that DEPDC1 promoted malignant progression and glycolysis of RCC, and knockdown DEPDC1 could reverse TKI resistance in RCC cell lines. Bulk RNA sequencing (RNA-seq) and non-targeted metabolomics sequencing suggested that DEPDC1 may regulate RCC glycolysis via AKT/mTOR/HIF1α pathway, a finding supported by protein-level analysis. Clinical tissue samples from 98 RCC patients demonstrated that DEPDC1 was associated with poor prognosis and predicted RCC metastasis. In conclusion, this multi-omics analysis suggests that DEPDC1 could serve as a novel target for TKI combined with targeted metabolic therapy in advanced RCC patients with TKI resistance.

Abstract 7584: The solute transported xCT (SLC7A11) modulates lysosome biogenesis and microRNA trafficking in drug resistant renal cell carcinoma

Abstract Multi-tyrosine kinase inhibitors (TKIs) like sunitinib bind to over 50 kinases and inhibit several receptors such as VEGFR-1, VEGFR-2, and VEGFR-3 receptors, PDGFRa and PDGFRb, RET, cKIT, and FLT3. TKIs are effective drugs for the treatment of renal cell carcinoma (RCC) but intrinsic/acquired resistance remains a major hurdle. One of the proposed models for TKI resistance is drug sequestration by lysosomes. The solute transporter xCT is a cystine/glutamate antiporter that plays a role in the production of antioxidants in cancer cells. Our lab has found that SLC7A11, the gene that encodes xCT, is overexpressed in sunitinib resistant RCC cells. LAMP1 expression was also increased in sunitinib resistant RCC cells, suggesting an upregulation of lysosome biogenesis. The biochemical knock down of SLC7A11 by shRNA showed a decrease in LAMP1 expression, suggesting a decrease in lysosome biogenesis. SEC24D is a key catalytic component of COPII complex involved in formation of exosomes and secretory pathways. Our preliminary data showed that reduction in xCT expression was associated with a decrease in SEC24D protein levels which was associated with a reduction in the extracellular export and, consequently, an increase in intracytoplasmic levels of miRNA 605, a known tumor suppressor. We are currently testing the hypothesis that xCT may modulate lysosomes biogenesis and micro-RNA trafficking in several clear cell and translation renal cell carcinoma models. In summary, a better understanding of the role of xCT in the regulation of intracytoplasmic organelles may lead to the identification of a novel therapeutic strategy to overcome TKI resistance in RCC. Citation Format: Abbas Jawadwala, Christopher Rupert, Remi Adelaiye-Ogala, Roberto Pili, Sreenivasulu Chintala, Ashley Orillion, May Elbanna, Nur Damayanti, Ilaria Delle Fontane. The solute transported xCT (SLC7A11) modulates lysosome biogenesis and microRNA trafficking in drug resistant renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7584.

Underlying mechanisms of novel cuproptosis-related dihydrolipoamide branched-chain transacylase E2 (DBT) signature in sunitinib-resistant clear-cell renal cell carcinoma.

Renal cell carcinoma (RCC) is the predominant form of malignant kidney cancer. Sunitinib, a primary treatment for advanced, inoperable, recurrent, or metastatic RCC, has shown effectiveness in some patients but is increasingly limited by drug resistance. Recently identified cuproptosis, a copper-ion-dependent form of programmed cell death, holds promise in combating cancer, particularly drug-resistant types. However, its effectiveness in treating drug resistant RCC remains to be determined. Exploring cuproptosis's regulatory mechanisms could enhance RCC treatment strategies. Our analysis of data from the GEO and TCGA databases showed that the cuproptosis-related gene DBT is markedly under expressed in RCC tissues, correlating with worse prognosis and disease progression. In our study, we investigated copper CRGs in ccRCC, noting substantial expression differences, particularly in advanced-stage tumors. We established a connection between CRG expression levels and patient survival, positioning CRGs as potential therapeutic targets for ccRCC. In drug resistant RCC cases, we found distinct expression patterns for DBT and GLS CRGs, linked to treatment resistance. Our experiments demonstrated that increasing DBT expression significantly reduces RCC cell growth and spread, underscoring its potential as a therapeutic target. This research sheds new light on the role of CRGs in ccRCC and their impact on drug resistance.

Abstract 2618: Tumor multicomponent targeting nanoparticle for synergistic killing of drug resistant renal cell carcinoma

Abstract Targeted therapy in renal cell carcinoma (RCC) has limited clinical response due to the development of drug resistance. Drug resistance can be acquired through multiple pathways including, impairment of apoptosis, overexpression of hypoxia promoting carbonic anhydrase 9 (CA9), and infiltration of folate receptor (FR) positive tumorigenic macrophages. Our hypothesis was to overcome the drug resistance by developing a tumor stimuli-responsive nanoparticle (NP) that can carry combination drugs, such as Cabozantinib (CB) and CFM 4.16 in RCC. The rationale of choosing the CB in combination with CFM4.16 was to induce synergistic anti-RCC effect by modulating the multiple tumor survival pathways, such as caspase 3, Akt/p-Akt, MET. One of the major challenges of the CB and CFM4.16 combination therapy is their poor water solubility and limited targetability to cancer. Thus, we came up with a smart strategy of developing dual folate receptor (FR) and carbonic anhydrase-9 (CA9) biomarker directed nanoparticles that can target the tumor stroma and hypoxia of RCC, respectively. In this proof of concept study, we synthesized SMA-TPGS and SMA polymer (PL) comprising of FR and CA9 dual targeting ligand, namely, FR-CA9-OL using reagent free ‘click' chemistry. FR-CA9-PL was encapsulated either with CFM4.16 or with CB to obtain nanoparticles, called FR-CA9-C4.16 and FR-CA9-CB respectively. The nanoparticles were prepared by using a co-solvent dialysis method that resulted in small-particle size with a range of 80-100 nm diameter, narrow polydispersity index of ∼ 0.15 and high drug loading of 30% (wt./wt.). The homogenous and high drug loading characteristics of nanoparticles are optimal for penetrating hypoxia of RCC. The IC50 of FR-CA9-C4.16 was improved by 60-fold as compared to CFM4.16 treatment and IC50 of FR-CA9-CB is improved by 16-fold compared to CB treatment in aggressive Everolimus-resistant (Evr-res) A498 RCC cells. The combination of FR-CA9-C4.16 with FR-CA9-CB demonstrated synergistic killing of Evr-res-A498 with CI value 0.1-0.5. The signature characteristic and superior anticancer effect of nanoparticles in Evr-resistant RCC provide a worthwhile strategy for overcoming drug resistance in RCC. Citation Format: Kushal Vanamala, Samaresh Sau, Shivani Naik, Arun K. Rishi, Arun Iyer. Tumor multicomponent targeting nanoparticle for synergistic killing of drug resistant renal cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2618.

Nuclear NADPH oxidase-4 associated with disease progression in renal cell carcinoma

Nuclear NADPH oxidase-4 (Nox4) is a key component of metabolic reprogramming and is often overexpressed in renal cell carcinoma (RCC). However, its prognostic role in RCC remains unclear. Here we examined the significance of nuclear Nox4 on disease progression and development of drug resistance in advanced RCC. We analyzed human RCC tissue from multiple regions in the primary index tumor, cancer-associated normal adjacent parenchyma, intravascular tumor in locally advanced cancer patients. We found that the higher nuclear Nox4 expression was significantly associated with progression and death. These findings were consistent after controlling for other competing clinical variables. In contrast, patients with lower nuclear Nox4, even in higher stage RCC had better prognosis. We identified a subset of patients with high nuclear Nox4 who had rapid disease progression or died within 6 months of surgery. In addition, higher nuclear Nox4 level correlated with resistance to targeted therapy and immunotherapy. Western blotting performed on fresh human RCC tissue as well as cell-lines revealed increased nuclear Nox4 expression. Our data support an important prognostic role of Nox4 mediated regulation of RCC independent of other competing variables. Nox4 localizes to the nucleus in high-grade, high-stage RCC. Higher nuclear Nox4 has prognostic significance for disease progression, poor survival, and development of drug resistance in RCC.

Extracellular Vesicles in Renal Cell Carcinoma: Multifaceted Roles and Potential Applications Identified by Experimental and Computational Methods.

Renal cell carcinoma (RCC) is the most common type of kidney cancer. Increasingly evidences indicate that extracellular vesicles (EVs) orchestrate multiple processes in tumorigenesis, metastasis, immune evasion, and drug response of RCC. EVs are lipid membrane-bound vesicles in nanometer size and secreted by almost all cell types into the extracellular milieu. A myriad of bioactive molecules such as RNA, DNA, protein, and lipid are able to be delivered via EVs for the intercellular communication. Hence, the abundant content of EVs is appealing reservoir for biomarker identification through computational analysis and experimental validation. EVs with excellent biocompatibility and biodistribution are natural platforms that can be engineered to offer achievable drug delivery strategies for RCC therapies. Moreover, the multifaceted roles of EVs in RCC progression also provide substantial targets and facilitate EVs-based drug discovery, which will be accelerated by using artificial intelligence approaches. In this review, we summarized the vital roles of EVs in occurrence, metastasis, immune evasion, and drug resistance of RCC. Furthermore, we also recapitulated and prospected the EVs-based potential applications in RCC, including biomarker identification, drug vehicle development as well as drug target discovery.

Resveratrol enhances chemosensitivity of renal cell carcinoma to paclitaxel.

By restraining proliferation and promoting apoptosis, resveratrol (RES) has anti-tumor effect in various cancers. Here, we examine whether RES exerts similar effect in drug-resistant renal cell carcinoma (RCC). To this end, Caki-1 cells derived from renal carcinoma are subjected to escalated doses of paclitaxel (PTX) to produce the PTX resistant Caki-1PTX cells. Both Caki-1 and Caki-PTX cells are sensitive to PTX, in a dose dependent manner. RES, dose-dependently, suppresses the expression of survivin, a molecular biomarker of cancer and a member of the inhibitor of apoptosis (IAP) family and its co-administration with PTX inhibits the effect of this drug on cell viability. To decipher whether survivin expressed by cancer cells is involved in rendering cells PTX sensitive, survivin is overexpressed. This dramatically counteracts the effects of RES on cell survival in the presence of PTX. Furthermore, decrease of survivin by inhibition of PI3K/AKT pathway significantly inhibits the effect of PTX in Caki-1PTX cells. These data show that RES increases the sensitivity of PTX resistant renal cells to drug treatment.

Degalactotigonin Exerts Effective Inhibition on the Growth, Metastasis and Sunitinib-Resistance of Renal Cell Carcinoma Through Inactivating YAP Signaling

Background: The pervasive progression and drug-resistance of renal cell carcinoma (RCC) after treatments demands for more effective drugs with little side effects. Recently, extracts from natural resources have been reported to effectively suppress the progression of certain tumors. In this study, we examined the effects of degalactotigonin extracted from Solanum nigrum L. on the progression and sunitinib-resistance of RCC, and the underlying mechanisms. Methods: The in vitro effects of degalactotigonin on the proliferation, apoptosis, invasion, migration and sunitinib-resistance were assessed by CCK-8, flow cytometry, Western blot, Matrigel invasion and transwell migration assays. The in vivo effects were evaluated in murine models of subcutaneous and in situ tumor and lung metastasis. The related molecular characteristics were delineated by RNA-sequencing. Findings: Degalactotigonin induced apoptosis and suppressed proliferation, invasion, migration, and sunitinib-resistance of RCC cells in vitro in a dose-dependent manner. Furthermore, degalactotigonin effectively inhibited the tumorigenicity and lung metastasis of RCC cells in vivo. Mechanistically, RNA-sequencing revealed that inactivation of YAP signaling occurred in degalactotigonin-treated RCC cells with reduced expression of YAP and its target genes. We also observed that degalactotigonin activated p-LATS1/2 to phosphorylate YAP, which induced more YAP retention in the cytoplasm but less YAP entering the nucleus of RCC cells. Moreover, re-expressed YAP in degalactotigonin-treated RCC cells mediated the anti-tumor activities of degalactotigonin on RCC. Furthermore, degalactotigonin ameliorated sunitinib-resistance in an orthotopic RCC model. Interpretation: Degalactotigonin is an effective therapeutic agent in inhibiting the growth, progression and sunitinib-resistance of RCC. Funding Statement: National Natural Science Foundation of China (No. 81773154, 81772747 and 81301861), Shanghai Natural Science Foundation of China (No. 13ZR1450700), the Shanghai Medical Guidance (Chinese and Western Medicine) Science and Technology Support Project (No. 17411960200). Declaration of Interests: The authors declare no potential conflicts of interest. Ethics Approval Statement: All experimental animal procedures were approved by the Animal Care and Use Committee of the Second Military Medical University (Shanghai, China).

Tumor hypoxia directed multimodal nanotherapy for overcoming drug resistance in renal cell carcinoma and reprogramming macrophages

Drug resistance is one of the significant clinical burden in renal cell carcinoma (RCC). The development of drug resistance is attributed to many factors, including impairment of apoptosis, elevation of carbonic anhydrase IX (CA IX, a marker of tumor hypoxia), and infiltration of tumorigenic immune cells. To alleviate the drug resistance, we have used Sorafenib (Sor) in combination with tumor hypoxia directed nanoparticle (NP) loaded with a new class of apoptosis inducer, CFM 4.16 (C4.16), namely CA IX-C4.16. The NP is designed to selectively deliver the payload to the hypoxic tumor (core), provoke superior cell death in parental (WT) and Everolimus-resistant (Evr-res) RCC and selectively downmodulate tumorigenic M2-macrophage. Copper-free ‘click’ chemistry was utilized for conjugating SMA-TPGS with Acetazolamide (ATZ, a CA IX-specific targeting ligand). The NP was further tagged with a clinically approved NIR dye (S0456) for evaluating hypoxic tumor core penetration and organ distribution. Imaging of tumor spheroid treated with NIR dye-labeled CA IX-SMA-TPGS revealed remarkable tumor core penetration that was modulated by CA IX-mediated targeting in hypoxic-A498 RCC cells. The significant cell killing effect with synergistic combination index (CI) of CA IX-C4.16 and Sor treatment suggests efficient reversal of Evr-resistance in A498 cells. The CA IX directed nanoplatform in combination with Sor has shown multiple benefits in overcoming drug resistance through (i) inhibition of p-AKT, (ii) upregulation of tumoricidal M1 macrophages resulting in induction of caspase 3/7 mediated apoptosis of Evr-res A498 cells in macrophage-RCC co-culturing condition, (iii) significant in vitro and in vivo Evr-res A498 tumor growth inhibition as compared to individual therapy, and (iv) untraceable liver and kidney toxicity in mice. Near-infrared (NIR) imaging of CA IX-SMA-TPGS-S0456 in Evr-res A498 RCC model exhibited significant accumulation of CA IX-oligomer in tumor core with >3-fold higher tumor uptake as compared to control. In conclusion, this proof-of-concept study demonstrates versatile tumor hypoxia directed nanoplatform that can work in synergy with existing drugs for reversing drug-resistance in RCC accompanied with re-education of tumor-associated macrophages, that could be applied universally for several hypoxic tumors.

Therapeutic Targeting of Sunitinib-Induced AR Phosphorylation in Renal Cell Carcinoma.

Androgen receptor (AR) plays a crucial role in the development and progression of prostate cancer. AR expression has also been reported in other solid tumors, including renal cell carcinoma (RCC), but its biological role here remains unclear. Through integrative analysis of a reverse phase protein array, we discovered increased expression of AR in an RCC patient-derived xenograft model of acquired resistance to the receptor tyrosine kinase inhibitor (RTKi) sunitinib. AR expression was increased in RCC cell lines with either acquired or intrinsic sunitinib resistance in vitro An AR signaling gene array profiler indicated elevated levels of AR target genes in sunitinib-resistant cells. Sunitinib-induced AR transcriptional activity was associated with increased phosphorylation of serine 81 (pS81) on AR. Additionally, AR overexpression resulted in acquired sunitinib resistance and the AR antagonist enzalutamide-induced AR degradation and attenuated AR downstream activity in sunitinib-resistant cells, also indicated by decreased secretion of human kallikrein 2. Enzalutamide-induced AR degradation was rescued by either proteasome inhibition or by knockdown of the AR ubiquitin ligase speckle-type POZ protein (SPOP). In vivo treatment with enzalutamide and sunitinib demonstrated that this combination efficiently induced tumor regression in a RCC model following acquired sunitinib resistance. Overall, our results suggest the potential role of AR as a target for therapeutic interventions, in combination with RTKi, to overcome drug resistance in RCC.Significance: These findings highlight the therapeutic potential of targeting the androgen receptor to overcome RCC resistance to receptor tyrosine kinase inhibitors. Cancer Res; 78(11); 2886-96. ©2018 AACR.

MP72-02 METABOLISM RE-PROGRAMMING AS A THERAPEUTIC TARGET FOR DRUG RESISTANT RENAL CELL CARCINOMA

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology II1 Apr 2018MP72-02 METABOLISM RE-PROGRAMMING AS A THERAPEUTIC TARGET FOR DRUG RESISTANT RENAL CELL CARCINOMA Hirofumi Yoshino, Kazutaka Miyamoto, Masaya Yonemori, Satoru Sugita, Takashi Sakaguchi, Hideki Enokida, and Masayuki Nakagawa Hirofumi YoshinoHirofumi Yoshino More articles by this author , Kazutaka MiyamotoKazutaka Miyamoto More articles by this author , Masaya YonemoriMasaya Yonemori More articles by this author , Satoru SugitaSatoru Sugita More articles by this author , Takashi SakaguchiTakashi Sakaguchi More articles by this author , Hideki EnokidaHideki Enokida More articles by this author , and Masayuki NakagawaMasayuki Nakagawa More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2286AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES It has been revealed that metabolism re-programming, such as Warburg effect, occurs in cancer cells. Recently, it was reported that anti-tumor effects of a HIF2a antagonist was greatly exceeded that of sunitinib in renal cell carcinoma (RCC) (Nature, 2016). However, drug-resistant acquisition will be a future problem. In this study, we aimed to elucidate the mechanism and conquest of drug resistant acquisition regarding HIF2a based on metabolism re-programming. METHODS First, we established a sunitinib-resistant RCC cell line (SU-R-786-o) in vivo by oral gavage treatment, followed by the establishment of HIF2a knockout cell line (HIF2a-KO-SU-R-786-o) by CRISPR/Cas9. We performed omics analyses using these cells. By using new inhibitors of phosphoglycerate dehydrogenase (PHGDH), which was selected as a candidate gene for drug resistance by omics analyses, we performed proliferation and apoptosis assay in vitro, and a xenograft assay. PHGDH-overexpressed cells by lentiviral vector were subjected to a colony formation assay. We also performed statistical analyses based on TCGA database of RCC patients. RESULTS SU-R-786-o showed significant sunitinib resistance both in vitro and in vivo. The expression of known HIF2a target genes was markedly suppressed in HIF2a-KO-SU-R-786-o. HIF2a-KO-SU-R-786-o significantly reduced cell proliferation compared to control cells, but it still survived, probably due to accelerated alternative pathways. Metabolomics analysis showed that metabolites were clearly divided among 786-o, SU-R-786-o, and HIF2a-KO-SU-R-786-o, and that serine biosynthesis was significantly activated in HIF2a-KO-SU-R-786-o. In addition, RNA sequence and quantitative proteome analyses showed that PHGDH, a key enzyme for serine synthesis, was accelerated in HIF2a-KO-SU-R-786-o. PHGDH inhibitor reduced cell growth in vivo and in vitro by inducing apoptosis in HIF2a-KO-SU-R-786-o more than in parent cells. Whereas, PHGDH overexpressed cells exhibited a significant increase in colony numbers compared to parent cells. TCGA database showed that patients with PHGDH gene amplification (n = 24) had poor overall survival (P = 0.0003) compared to patients without amplification (n = 500). CONCLUSIONS Metabolism re-programming occurred in drug-resistant RCCs. In addition, PHGDH can be a therapeutic target for patients showing activated serine biosynthesis after HIF2a deficiency. Furthermore, PHGDH inhibitor should be considered as a first treatment in patients with PHGDH amplification. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e952 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Hirofumi Yoshino More articles by this author Kazutaka Miyamoto More articles by this author Masaya Yonemori More articles by this author Satoru Sugita More articles by this author Takashi Sakaguchi More articles by this author Hideki Enokida More articles by this author Masayuki Nakagawa More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Targeting metabolism re-programming as a therapy for drug-resistant renal cell carcinoma

Targeting metabolism re-programming as a therapy for drug-resistant renal cell carcinoma

Interleukin-6 induces drug resistance in renal cell carcinoma.

Metastatic renal cell carcinoma (mRCC) is a tumor entity with poor prognosis due to limited therapy options. Tyrosine kinase inhibitors (TKIs), the novel targeted agents have been used for the treatment of mRCC and have shown efficacy. Interferon (IFN)-α is also one of the most frequently used agents in immunotherapy. However, drug resistance needs to be overcome to achieve a sufficiently positive effect. Interleukin-6 (IL-6), which induce suppressor of cytokine signaling-3 (SOCS3) expression, is one of the factors associated with poor prognosis of patients with renal cell carcinoma (RCC). To analyze the influence of IL-6 in drug resistance of RCC, anti-IL-6 receptor antibody was used in combination with IFN or TKIs. The SOCS3 mRNA expression level was significantly increased by IFN-α stimulation in 786-O RCC cells which were resistant to IFN, but not in ACHN cells that were sensitive to IFN. The overexpression of SOCS3 by gene transfection in ACHN significantly inhibited the growth-inhibitory effect of IFN-α. An in vivo study demonstrated that co-administration of SOCS3-targeted siRNA promoted INF-α-induced cell death and growth suppression in 786-O cell xenograft. SOCS3 could be a key component in the resistance to interferon treatment of renal cell carcinoma. Because SOCS3 is rapidly up-regulated by IL-6 and a negative regulator of cytokine signaling, IL-6 expression on RCC cells was also analyzed and the 786-O cells showed the high level of IL-6 mRNA expression under the condition of interferon stimulation. IL-6R antibody, tocilizumab, significantly suppressed cell proliferation in 786-O cells by interferon stimulation accompanied with phosphorylation of STAT1 and inhibited SOCS3 expression. The in vivo effects of combination therapy with tocilizumab and interferon showed significant suppression of 786-O tumor growth in a xenograft model. We also hypothesized that TKI resistance and IL-6 secretion are causally connected. And we found that 786-O RCC cells secrete high IL-6 levels after low dose stimulation with the TKIs sorafenib, sunitinib and pazopanib, inducing activation of AKT-mTOR pathway, NFκB, HIF-2α and VEGF expression. Tocilizumab neutralizes the AKT-mTOR pathway activation and results in reduced proliferation. A combination therapy with tocilizumab and TKI suppresses 786-O tumor growth and inhibits angiogenesis in vivo more efficient than TKI alone. Our findings suggest that IL-6 could induce drug resistance on RCC, and combination therapy of IL-6R inhibitors and IFN/TKIs may represent a novel therapeutic approach for RCC treatment.

Sodium butyrate enhances the growth inhibitory effect of sunitinib in human renal cell carcinoma cells.

Sunitinib (SU) is a small molecule that inhibits the receptor tyrosine kinase (RTK) signaling pathway, and has been clinically used to treat advanced renal cell carcinoma (RCC). However, SU is not always effective as RCC is a highly chemoresistant type of cancer. One of the factors that confer chemoresistance to RCC is a hypoxic condition. Lack of oxygen activates hypoxia-inducible factor (HIF) protein, which is followed by the upregulation of growth factors, including vascular endothelial growth factor and activation of the RTK signaling pathway. In this context, histone deacetylase inhibitors (HDACIs) are considered prominent combined agents for SU as they downregulate the expression of HIFs. Therefore, the present study aimed to investigate the effectiveness of combined treatment with SU and sodium butyrate (NaBu), an HDACI. Long-term exposure to these agents exerted a stronger growth inhibitory effect in RCC cell lines compared with single treatment groups. Furthermore, combined treatment suppressed HIF-2α protein, which was induced under hypoxic conditions. In addition, this combination sustained the activity of the RTK signaling pathway to the level of intact cells, although a single treatment with SU or NaBu was demonstrated to increase this activity. Overall, it is suggested that the combination of SU and NaBu is effective for overcoming drug resistance in RCC.

The network of DAB2IP-miR-138 in regulating drug resistance of renal cell carcinoma associated with stem-like phenotypes.

Targeted therapy is a standard of care for metastatic renal cell carcinoma (RCC) but the response rate is not overwhelmed, which only prolongs a short survival of patients due to the onset of therapeutic resistance. Although the mechanisms are not fully understood, the presence of cancer initiating cells (CIC) may underlie the drug resistance. Nevertheless, identifying CIC phenotypes with its biomarkers in RCC appear to be diverse and controversial from many reports. In this study, we took a different approach to focus on the regulatory mechanism in RCC-CIC and unveil DAB2IP-mediated miR-138 expression that plays a critical role in modulating stem-like phenotypes in RCC via targeting the ABC transporter (ABCA13) as well as oncogenic histone methyltransferase EZH2 while down regulation of miR-138 gene expression in RCC is due to epigenetic gene silencing by DNA methyltransferase 1 (DNMT1). We also characterize the individual mechanism by which ABCA13 in RCC-CIC contributes to its drug resistance and. EZH2 maintain stem-like phenotypes. Noticeably, elevated expression of ABCA13 and EZH2 is correlated with overall survival of RCC patients, which can be used as potential prognostic markers. Taken together, this study demonstrates a potent and unique pathway of DAB2IP-mediated miR-138 in modulating CIC phenotypes during RCC progression and also offers a new therapeutic strategy of targeting drug resistant RCC.

Targeting 3-phosphoinositide-dependent protein kinase 1 associated with drug-resistant renal cell carcinoma using new oridonin analogs

The current agents used for renal cell carcinoma (RCC) only exhibit the moderate response rate among patients. Development of drug resistance eventually fuels the need of either more potent drugs or new drugs to target the resistant pathways. Oridonin is a diterpenoid isolated from the Chinese medicinal herb Rabdosia rubescens and has been shown to have antitumor activities in many cancers. We previously developed new synthetic methodologies to modify structurally diversified diterpenoids and designed a series of nitrogen-enriched oridonin analogs. In this study, we screened a variety of oridonin analogs based on their cytotoxicity using MTT assay and identify the most potent candidate, namely, CYD-6-17. CYD-6-17 exhibited a high potency to inhibit the in vitro growth of several drug-resistant RCC cells as well as endothelial cells stimulated by tumor cells at nanomolar range. Delivery of CYD-6-17 significantly inhibited RCC tumor growth using xenograft model. Mechanistically, it targeted the 3-phosphoinositide-dependent protein kinase 1 gene that appeared to be a potent regulator of AKT and was associated with patient survival after targeted therapies. This offers a new rational therapeutic regimen of CYD-6-17 to drug-resistant RCC based on its novel mechanism of action.

Abstract 3078: Epigenetic regulation of miR-138 confers cancer stem cell characteristics of renal cell carcinoma

Abstract Chemotherapy is the standard care for metastatic disease, in renal cell carcinoma (RCC), the outcome of chemotherapy only prolongs short survival of patients. The reason for the resistance of RCC to chemotherapy is not fully understood, although it has been speculated that overabundance of ATP-binding cassette (ABC)/p-glycoprotein transporter system in RCC might be the reason to repel various chemotherapeutic agents away from the cancer cell. Meanwhile, cancer stem cells (CSC) theory has also focused a significant attention in recent years as a potential explanation for drug resistance and metastasis of RCC. In this study, we demonstrate that drug resistant RCC cells exhibit CSC phenotypes and miR-138 that is significantly downregulated in RCC acted critical role in suppressing CSC phenotype by targeting ABC transporter ABCA13 and oncogenic histone methyltransferase EZH2. Importantly, miR-138 levels were significantly enhanced by treatment of DNA hypomethylating agent (i.e., 5-aza) or histone deactylases inhibitor (i.e., TSA). Epigenetic silencing of tumor-suppressive micro-RNAs has been shown a key oncogenic mechanism for the activation of oncogenes in tumors. Indeed, depletion of miR-138 promoted CSC phenotype followed by enhanced expressions of ABCA13 and EZH2. Furthermore, a novel tumor suppressor DAB2IP can inhibit DNA methyltransferase 1 (DNMT1) activity, which results in miR-138 expression. Taken together, this study identifies the new role of miR-138 in RCC-CSC and unveils a unique regulation of tumor suppressor protein in DNMT1. Overall study provides not only a new biomarker of RCC-CSC and but also potential therapeutic strategy of targeting drug resistant RCC. Citation Format: Eun-Jin Yun, Jiancheng Zhou, Chun-Jung Lin, Elizabeth Hernandez, John Santoyo, Jer-Tsong Hsieh. Epigenetic regulation of miR-138 confers cancer stem cell characteristics of renal cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3078. doi:10.1158/1538-7445.AM2015-3078

Resistance after Chronic Application of the HDAC-Inhibitor Valproic Acid Is Associated with Elevated Akt Activation in Renal Cell Carcinoma In Vivo

Targeted drugs have significantly improved the therapeutic options for advanced renal cell carcinoma (RCC). However, resistance often develops, negating the benefit of these agents. In the present study, the molecular mechanisms of acquired resistance towards the histone deacetylase (HDAC) inhibitor valproic acid (VPA) in a RCC in vivo model were investigated. NMRI:nu/nu mice were transplanted with Caki-1 RCC cells and then treated with VPA (200 mg/kg/day). Controls remained untreated. Based on tumor growth dynamics, the mice were divided into “responders” and “non-responders” to VPA. Histone H3 and H4 acetylation and expression of cell signaling and cell cycle regulating proteins in the RCC mouse tumors were evaluated by Western blotting. Tumor growth of VPA responders was significantly diminished, whereas that of VPA non-responders even exceeded control values. Cdk1, 2 and 4 proteins were strongly enhanced in the non-responders. Importantly, Akt expression and activity were massively up-regulated in the tumors of the VPA non-responders. Chronic application (12 weeks) of VPA to Caki-1 cells in vitro evoked a distinct elevation of Akt activity and cancer cells no longer responded with cell growth reduction, compared to the short 2 week treatment. We assume that chronic use of an HDAC-inhibitor is associated with (re)-activation of Akt, which may be involved in resistance development. Consequently, combined blockade of both HDAC and Akt may delay or prevent drug resistance in RCC.

Size-controlled, dual-ligand modified liposomes that target the tumor vasculature show promise for use in drug-resistant cancer therapy

Anti-angiogenic therapy is a potential chemotherapeutic strategy for the treatment of drug resistant cancers. However, a method for delivering such drugs to tumor endothelial cells remains to be a major impediment to the success of anti-angiogenesis therapy. We designed liposomes (LPs) with controlled diameter of around 300nm, and modified them with a specific ligand and a cell penetrating peptide (CPP) (a dual-ligand LP) for targeting CD13-expressing neovasculature in a renal cell carcinoma (RCC). We modified the LPs with an NGR motif peptide on the top of poly(ethylene glycol) and tetra-arginine (R4) on the surface of the liposome membrane as a specific and CPP ligand, respectively. The large size prevented extravasation of the dual-ligand LP, which allowed it to associate with target vasculature. While a single modification with either the specific or CPP ligand showed no increase in targetability, the dual-ligand enhanced the amount of delivered liposomes after systemic administration to OS-RC-2 xenograft mice. The anti-tumor activity of a dual-ligand LP encapsulating doxorubicin was evaluated and the results were compared with Doxil®, which is clinically used to target tumor cells. Even though Doxil showed no anti-tumor activity, the dual-ligand LP suppressed tumor growth because the disruption of tumor vessels was efficiently induced. The comparison showed that tumor endothelial cells (TECs) were more sensitive to doxorubicin by 2 orders than RCC tumor cells, and the disruption of tumor vessels was efficiently induced. Collectively, the dual-ligand LP is promising carrier for the treatment of drug resistant RCC via the disruption of TECs.

Potentiation of the sensitivity of renal cell carcinoma cells to TRAIL-mediated apoptosis by subtoxic concentrations of 5-fluorouracil

Cytotoxic chemotherapy has shown little antitumour activity against renal cell carcinoma (RCC). Although immunotherapy is relatively effective against RCC, the response rate is approximately 20%. Therefore, there is an urgent need to increase this response rate. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo-2L) is one member of the tumour necrosis factor ligand family that selectively induces apoptosis of cancer cells. Since several cytotoxic anticancer drugs including 5-fluorouracil (5-FU) also mediate apoptosis, we reasoned that combined treatment of cancer cells with TRAIL and drugs might result in synergy and overcome the resistance of the cancer cell. This study has examined whether TRAIL can synergise with 5-FU in both cytotoxic and apoptotic assays against drug-resistant RCC cells. Cytotoxicity was determined by an 1-day microculture tetrazolium dye assay. Synergy was assessed by isobolographic analysis. Treatment of Caki-1 cells with TRAIL in combination with 5-FU resulted in a synergistic cytotoxic effect. Synergy was also achieved in freshly derived RCC cells from 3 patients. The enhanced cytotoxicity was obtained irrespective of the sequence of the treatment, but the highest cytotoxicity was observed when Caki-1 cells were treated with TRAIL and 5-FU simultaneously. The synergy achieved in cytotoxicity with TRAIL and 5-FU was shown to be due to apoptosis. The mechanisms responsible for the synergistic cytotoxicity and apoptosis were examined. Treatment of Caki-1 cells with 5-FU enhanced the expression of p53 and bax, but had no effect on the expression of bcl-2. Incubation of Caki-1 cells with TRAIL enhanced the intracellular accumulation of 5-FU and 5-fluoro-2′-deoxyuridine 5′-monophosphate (FdUMP). Treatment of Caki-1 cells with TRAIL downregulated the expression of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) modestly, and upregulated the expression of orotate phosphoribosyltransferase (OPRT). However, the expression level of thymidine phosphorylase (TP) was not affected by TRAIL. This study demonstrates that combined treatment of RCC cells with TRAIL and 5-FU overcomes their resistance. The sensitisation obtained with freshly isolated RCC cells required low subtoxic concentrations of 5-FU. These findings support the potential application in vivo of a combination of TRAIL and 5-FU in the treatment of TRAIL/5-FU-resistant RCC.